Water quality in a reservoir is affected by many things. Influent contaminants, throughput, detention time, stratification, temperatures, depth, morphology, bathometry, rainfall, wind, turnover, toxins, sunlight, microbes, aquatic life, plants, organics, metals, outfall characteristics, and surface area are just some of the countless factors that contribute to its quality. Each reservoir establishes its own limnological balance based on these conditions, but oftentimes supplemental or external input is required to maintain a desirable reservoir water quality. Examples of supplemental or external inputs include chemicals, aeration, mixing, and many other inputs.
Reservoirs can exist in many different forms. They can be ponds or lakes where water is stored for recreational or drinking water purposes. They can be lagoons where treatment of wastewater is performed. They can even be small like a clarification basin in a water treatment plant used to settle out solids and debris. Different forms of reservoirs experience different challenges in establishing or maintaining optimal water quality. Lastly, reservoirs can contain many different liquids. Oftentimes it is water, but in other instances reservoirs can contain liquid chemicals and other liquid variations.
One of the most important elements of a reservoir is its water-air interface. The surface of a reservoir is a very dynamic spot where evaporation occurs, cooling/heating occurs, sunlight is transmitted and reflected, oxygenation occurs, photosynthesis occurs, waves are generated, gases are released, plant life and weeds grow, UV disinfection occurs, birds rest and feed, and so forth. The condition of a reservoir's surface has significant impact on the water quality and characteristics beneath. For example, if the surface in a wastewater treatment lagoon is covered by Duckweed (i.e., Limnoideae), sunlight can't get through, photosynthesis is hindered, and treatment efficiencies deteriorate. If there is a strong wind across a lake, waves are generated and the lake gets mixed. If the surface is covered in ice, gases in the lake can't get out, oxygen and sunlight can't get in, and conditions change dramatically. The surface is where oil finds itself in an oil spill. Considering how dynamic and important the water-air interface is, it would be highly beneficial if there was a way to control or influence the activity taking place across it. Doing so successfully could have a dramatic impact on regulating a reservoir's overall water quality.
Further, debris on a water surface can create problematic conditions within the water body. Water bodies rely heavily on algae for oxygen generation and algae rely on sunlight. If sunlight is blocked from getting to the algae within the water body, the available oxygen is quickly taken up, aerobic microbes die off, and septic conditions can develop. Septic conditions cause a variety of problems and are usually not desirable.
Lagoon wastewater treatment systems are examples of water bodies that rely heavily on photosynthesis. These systems have a delicate limnological balance between nutrients, microbes, sunlight, mixing, and so forth. Contaminants such as ammonia and the biological oxygen demand within wastewater are typically processed and addressed by aerobic bacteria (heterotrophs, nitrobacter, etc.). If there is insufficient oxygen, there can be insufficient nitrification and BOD removal, and effluent permits can be violated. It is therefore important to ensure appropriate photosynthesis occurs within a lagoon treatment system.
Duckweed (i.e., Limnoideae) and other floating weeds can flourish in the presence of nutrients and sunlight, particularly in warm, stagnant environments like lagoon wastewater treatment systems. These floating weeds grow quickly and can cover a lagoon in little time. Sunlight is blocked and before long, there is insufficient oxygen present in the lagoon and effluent water quality deteriorates. Duckweed is not all bad, however. It is very effective in removing nutrients, so it would therefore be advantageous to harness the duckweed in a lagoon for treatment purposes yet “corral” it in a way so as to not inhibit photosynthesis.
In wastewater treatment, floating, moving media may be utilized to enhance treatment. Known floating media provide a haven for attached-growth biomass and can contribute to significantly greater processing rates. The media moves throughout a basin usually in the presence of air and is usually restrained by some sort of screen. By having the media house biomass, long sludge retention times can be achieved, which can be beneficial to treatment. The fact that the media moves throughout the basin and collides with other media is also beneficial as it allows for sloughing of old biomass and exposes the biomass to nutrients throughout the water column.
Even with known floating media, lagoon treatment systems can experience difficulty meeting effluent water quality requirements. Most every wastewater plant has a permit from a regulatory agency that requires their effluent be of a certain water quality. Sometimes it can be difficult to achieve permit requirements for Total Suspended Solids (TSS), Biological Oxygen Demand (BOD), pH, Total Kehedal Nitrogen (TKN), Ammonia, and so forth. It would therefore be beneficial for a lagoon treatment system to have the capability to achieve enhanced treatment, for example, via floating media, when and if needed.
In addition, aeration of water (liquid), for example, in a reservoir, is also an important step to ensure water quality. Aeration of water is accomplished in many ways. Two common methods of forced aeration are mechanical floating aerators and fixed-bottom aerators. Floating aerators sometimes fling water up into the air. Other times they force air down into the water from above. Fixed-bottom aerators are typically fine- or coarse-bubble aerators that are typically installed onto the bottom of a basin. These devices release air compressed from a blower into the water column and as the air rises, it oxygenates the water. Countless devices have been used to accomplish mechanical aeration of water.
Floating aerators can be burdensome and expensive to operate and maintain. Usually they are mechanical devices involving motors and gearboxes, which need typical manufacturer scheduled maintenance performed on them to ensure reliability. Because they are typically heavy mechanical devices located out in the water, they are typically extracted from the basins with cranes or heavy lifting equipment so maintenance can be accomplished on the shore. These devices can have water pumped through them and if there are rags and other debris present in the water, they can become clogged and inoperable—again requiring extraction from the basin for shore maintenance.
Fixed-bottom aerators also require maintenance, which means they require access. To access fixed-bottom aerators, water must be drained from the tank. Taking a basin out of service to enact maintenance on aeration equipment can create serious operational challenges for plants. Having a basin off-line can cause greater loading to the other basins in operation, which can make treating the water more challenging. Not meeting treatment goals can cause violations, trigger environmental fines, and contaminate the environment.
The prior art provides numerous known devices for treating liquid reservoirs, however, known devices have one or more shortcomings. The following known devices are worth noting:
Circulators/Solar Circulators—Circulation technologies (Solar powered circulation technologies) can be used to improve water quality in a reservoir. It is also used in wastewater lagoons to achieve mixing. This would not achieve the desired effect because these devices attempt to circulate layers of water, one on top of the other, in opposing directions. Also, as these devices are placed in a reservoir, currents are produced radially outward from a unit towards the other units placed in the reservoir, which contradict the movement of water. This causes a loss or reduction in efficiency. These devices attempt to control the limnological condition of a reservoir by obstructing the movement of microbes and facilitating greater exposure of microbes to predatory microorganisms, amongst other techniques. In any case, these circulators do not attempt to control the activity of the surface of a reservoir, but rather they attempt to enact specific movement of water below it. (In contrast, systems and methods of the present invention specifically target the activity of the surface, and then the sunlit depths below, and then it can selectively introduce nutrients to this treatment zone.) Solar circulators do not control the surface, and do not attempt to harness what goes on in just the sunlit depths of a reservoir, and do not selectively introduce nutrients on a select, periodic, or as-needed basis to achieve a certain water condition in the sunlit depths. Further, wave creation is not a goal or targeted output of solar circulation. Enacting waves at the surface, and waves of a specific height, period, or shape, are not required or necessarily desired in circulators. (In contrast, systems and methods of the present invention can manipulate light entry into a basin to affect limnology.)
Brush Aerators—This is a technology that spins around and flings water up in the air to add oxygen to the water. It flings it up in a certain direction, which can produce currents in the water as it comes down onto the surface. However, these devices aerate and mix water on an “unconfined” basis, and with no strategy within the reservoir. They simply add oxygen and mix water around it. (In contrast, systems and methods of the present invention can harness the sunlit depths of a reservoir into a specific current and treatment zone, brush aerators are aeration and mixing devices.) They also do nothing to manipulate light entry into the basin to affect biological activity.
Solar Shaking Devices—This is a solar powered shaking device that creates ripples in water for aesthetic purposes. However, this cosmetic device is not intended to, nor does it effectively treat water beneath it. (In contrast, systems and methods of the present invention can produce waves of a sufficient size, so as to affect light penetration into the water and photosynthesis, and heat transfer in the water, and is activated selectively based on environmental conditions to positively affect water characteristics.) The solar shaker shakes the surface of the water, producing ripples, with solar energy only, and is not activated according to any algorithm or strategy to affect the water characteristics beneath it.
Efforts continue to further develop liquid treatment systems, components for use in liquid treatment systems, and methods of effectively and efficiently treating liquids. For example, efforts continue to further develop water aeration devices, in particular, water aeration devices that enable one or more benefits such as (1) the water aeration device is accessible from the shore, (2) the water aeration device is easily extracted from a reservoir, (3) maintenance on the water aeration device does not require a liquid/water basin to be dewatered/drained, (4) the water aeration device would be designed to minimize or eliminate clogging from debris, and (5) the water aeration device could be maintained/serviced while other aerators continue to remain in operation.